UNIVERSITY  OF  CALIFORNIA  agricultural  Experiment  Station 

/~<-li    i   e-<~c-      *sc      ..(,,/.,.,  -•-■•»_  BENJ.    IDE    WHEELER,    PRESIDENT 

COLLEGE    OF    AGRICULTURE  thomas   forsyth   hunt,  dean  and  director 

___„_.     _y  H.     E.     VAN     NORMAN,    VlC  E-  Dl  R  ECTOR   AND    DEAN 
OCnl\LLt Y  University    Farm    School 


CIRCULAR  No.  122 

(October,  1914) 

THE    MANAGEMENT   OF   STRAWBERRY    SOILS 

IN   THE    PAJARO   VALLEY    AND 

ITS    PROBLEMS 

BY 

CHAS.   B.   LIPMAN 


INTRODUCTION 
The  methods  now  in  vogue  for  the  management  of  strawberry 
soils  in  the  Pajaro  Valley  have,  it  is  believed,  resulted  in  certain 
reductions  in  their  productive  capacity  due  apparently  to  unknown 
causes.  Such  decreases  in  productive  capacity,  which  have  caused 
much  uneasiness  among  strawberry  growers  there,  become  manifest, 
it  is  claimed,  more  particularly  in  the  second  planting  on  the  same 
piece  of  land.  In  other  words,  the  opinion  is  current  that  it  does  not 
pay  to  plant  strawberries  twice  in  succession  on  the  same  piece  of  land. 
In  order  to  obtain  some  idea  with  reference  to  the  status  of  this 
problem,  the  writer  visited  several  of  the  prominent  growers  of  the 
district  in  question  and  together  with  them  went  over  their  plantings 
in  order  to  make  the  necessary  observations  and  field  studies.  It 
was  hoped  that  such  visits  together  with  certain  physical  and  chemical 
examinations  which  were  made  on  soil  samples  from  representative 
strawberry  patches  might  throw  some  light  on  the  real  nature  of  the 
difficulties.  At  least  they  should  allow  of  the  formulation  of  an 
unbiassed  statement  with  reference  to  the  whole  matter  which  can 
serve  as  a  guide  to  the  strawberry  grower.  With  this  end  in  view 
the  writer  presents  the  brief  subjoined  statement  based  on  a  prelim- 
inary study  of  the  situation  under  consideration  and  hopes  that, 
pending  such  time  as  the  problem  may  be  more  definitely  solved,  his 
recommendations  may  prove  of  value  to  the  strawberry  industry  of 
the  Pajaro  Valley. 

THE  PHYSICAL  AND  CHEMICAL  CONDITION  OF  THE  SOIL 
The  physical  nature  of  the  soils  used  in  strawberry  growing  in 
the  Pajaro  Valley  varies  from  clay  loam  to  stiff  clay.     The  soils  are 
all  very  rich  in  organic  matter,  and   when   planting   is  begun   their 


physical  condition  is  splendid.  Most  of  the  soils  are  deep.  When, 
however,  they  are  planted  in  strawberries  the  physical  condition  may 
be  seriously  injured  by  certain  methods  of  handling',  more  fully  dis- 
cussed below.     The  soils  hold  water  very  tenaciously. 

The  chemical  condition  of  the  soils  in  question  is  excellent.  We 
have  made  analyses  of  soils  from  both  the  Reiter  and  Burland  ranches 
for  both  the  total  and  the  available  plant  food  supply  and  have  found 
them  very  rich  in  all  respects,  as  was  to  be  expected  from  their  origin 
and  position.  They  are,  indeed,  among  the  richest  soils  of  which  we 
have  knowledge  from  the  point  of  view  of  both  the  total  and  the 
available  nitrogen,  phosphoric  acid,  potash,  and  lime  supply.  More- 
over, in  making  analyses  of  soils  cropped  for  three  and  four  years, 
and  new  land  just  being  planted  to  strawberries  for  the  first  time,  we 
could  find  no  lack  of  total  and  available  plant  food  in  any  of  the 
soils.  The  heavy  production  for  three  years  does  not  seem  to  have 
seriously  affected  the  supply  of  plant  food  in  the  soil.  No  alkali  was 
found  in  several  of  the  soils  examined  and  it  is  indeed  rare  to  find 
seriously  large  quantities  of  soluble  salts  in  any  of  the  strawberry 
soils  of  the  Pajaro  Valley. 

INTERVIEWS  WITH  GROWERS  AND  THEIR  RESULTS 

Seven  of  the  leading  growers  of  strawberries  in  the  Pajaro  Valley 
were  interviewed  by  the  writer  in  their  respective  fields  and  the  fol- 
lowing points  brought  to  light  as  a  result: 

1.  All  but  one  or  two  of  the  growers  felt  more  or  less  strongly 
that  a  soil  is  .injured  for  the  same  plant  if  one  crop  of  strawberries 
has  been  grown  on  it  for  three  to  five  years. 

2.  Very  little  indisputable  evidence  of  such  a  condition  is  available. 

3.  More  than  half  of  the  growers  interviewed  could  not  of  their 
own  knowledge  point  to  a  patch  of  berries  which  was  the  second  in 
succession  on  the  same  piece  of  land  that  was  giving  evidence  of 
marked  decreases  in  yields  (as  compared  with  the  first  crop). 

4.  Of  the  balance  of  the  growers  only  two  could  definitely  point 
to  strawberry  patches  in  which  one  planting  had  immediately  fol- 
lowed another.  In  these  cases  it  was  stated  that  the  second  planting 
did  not  yield  nearly  as  well  as  the  first.  However,  owing  to  a  change 
in  the  variety  of  strawberry  from  one  planting  to  another,  or  to 
marked  changes  in  the  methods  of  management,  one  could  not  be  sure 
whether  the  second  planting  was  being  injured  by  factors  bequeathed 
to  it  by  the  first  crop  or  was  suffering  by  comparison  as  a  result  of 
the  changes  mentioned. 


3 

All  the  statements,  therefore,  which  were  made  to  me  by  growers, 
taken  together  with  my  own  observations,  when  boiled  down  and 
crystallized,  yield  the  following  conclusions : 

1.  Some  deterioration  for  the  same  crop  does  occur  in  the  yielding 
power  of  land  after  one  crop  of  strawberries  has  been  grown  on  the 
land. 

2.  The  cause  for  this  is  unknown. 

3.  The  condition  cannot,  in  the  light  of  present  knowledge,  justi- 
fiably be  claimed  to  be  the  result  of  a  direct  injurious  effect  of  the 
strawberry  plant  on  the  soil. 


METHODS  OF  SOIL  MANAGEMENT  NOW  IN  VOGUE 

The  berries  are  planted  on  ridges  about  18  inches  wide,  with  two 
rows  on  each  ridge.  The  uncropped  space  between  the  ridges  is  there- 
fore a  natural  depression  which  is  used  as  an  irrigation  ditch.  Water 
is  run  into  these  ditches  twice,  thrice  or  even  more  times  a  week,  every 
time  until  the  ditch  is  full  throughout  its  entire  length,  the  water 
standing  only  an  inch  or  less  below  the  surface  of  the  ridges.  As 
the  water  slowly  disappears  either  through  percolation  or  evaporation 
the  ditch  bottom  is  allowed  to  become  dry  and  hard  under  the  influ- 
ence of  the  sun.  Owing  to  its  large  clay  content  shrinkage  follows 
such  drying  and  baking  and  the  whole  surface  of  the  soil  becomes 
badly  checked.  No  cultivation  in  the  ditch  spaces  between  the  ridges 
is  practiced.  The  berry  pickers  aggravate  the  packed  condition  of 
the  soil  between  the  ridges  by  walking  over  and  squatting  on  it  as 
they  work.  Aside  from  the  thorough  preparation  through  tillage  of 
the  soil  at  the  time  of  planting,  no  other  treatment,  save  irrigation,  is 
given  the  soil,  except  in  some  instances  in  which,  in  recent  years, 
fertilizers  have  been  applied,  apparently  erratically,  to  the  soil  on 
the  ridges. 

Apple  trees  are  usually  set  out  at  the  time  when  a  new  strawberry 
patch  is  started,  especially  when  land  is  leased.  This  insures  to  the 
owner  of  the  land  a  young  apple  orchard  about  ready  to  bear  at  the 
expiration  of  the  four  or  five  years'  lease  of  the  strawberry  grower. 
It  may  be  said  in  passing  that  most  of  the  apple  orchards  of  the 
Pajaro  Valley  originated  in  this  way.  Owing  to  these  apple  plant- 
ings, moreover,  it  is  so  difficult  to  find  land  there  which  has  been  in 
strawberries  more  than  once  and  on  which  reliable  information  may 
be  obtained  with  reference  to  the  alleged  unsuitability  of  land  bearing 
strawberries  once  for  another  crop  of  that  same  plant.  The  lessees 
of  land  naturally  complain  about  even  the  possibility  of  such  deteri- 


oration  because  their  irrigation  systems  are  installed  at  very  consid- 
erable cost  and  the  investment  would  seem  to  be  more  than  even  big 
crops  during  three  or  four  years  would  justify. 


THE  WEAKNESS  OF  THE  PRESENT  METHOD  OF  MANAGEMENT 

The  chief  weakness  of  the  present  method  of  handling  these  soils 
as  briefly  outlined  above  is  to  be  found  in  the  fact  that  it  militates 
against  a  proper,  supply  of  air  in  the  soil.  The  air  is  necessary  to 
insure  healthy  and  large  root  systems,  good  bacterial  action,  and  the 
proper  chemical  reactions  for  the  supply  of  plant  food  to  the  plants. 
The  reason  for  the  poor  air  supply  in  the  soils  in  question  under  the 
present  method  of  management  is  twofold.  The  too  frequent  irriga- 
tion waterlogs  the  soil  and  drives  out  the  necessary  air.  The  com- 
paction and  non-cultivation  of  the  ditches  between  the  ridges  does 
not  leave  large  enough  spaces  to  hold  air  and  makes  it  difficult  for 
the  latter  to  penetrate  into  the  soil. 


PROPOSED  IMPROVEMENT  IN  METHODS  OF  SOIL  HANDLING 

It  is  obvious  from  what  has  been  said  above  that  improvement  in 
the  method  of  handling  the  strawberry  soils  must  be  chiefly  along  the 
lines  of  improving  the  air  conditions.  The  writer  suggests  therefore 
the  following  procedure : 

1.  Irrigation  not  oftener  than  once  every  two  weeks.  Less  frequent 
irrigation  is  desirable. 

2.  Deep  cultivation  with  one-horse  cultivator  of  the  ditch  soil.  To 
be  carried  out  as  soon  as  a  horse  can  walk  in  the  space  without  pud- 
dling the  soil. 

3.  Thorough  hoeing  on  the  ridges  between  the  plants.  This  is 
especially  important  in  the  case  of  new  plantings. 

In  addition  to  these  methods  of  soil  management  during  the  ordi- 
nary life  of  a  strawberry  patch  the  following  procedure  should  be 
followed  in  cases  in  which  it  is  desired  to  follow  one  crop  of  straw- 
berries by  another.  In  the  late  fall  of  the  year  in  which  a  patch  has 
''run  out,"  the  land  should  be  deeply  plowed  (preferably  10  to  12 
inches  in  depth),  thoroughly  harrowed,  and  sowed  to  bur  clover. 
Canada  field  peas  or  any  other  legume  which  will  make  a  heavy  winter 
growth.  The  earlier  this  is  done  in  the  fall  the  better.  In  the  spring 
the  cover  crop  should  be  deeply  plowed  under  and  then  the  soil  prop- 
erly prepared  for  planting  the  new  crop. 


